A variety of devices have been designed and used to attach a vehicle suspension systems between the vehicle body and an axle. Many vehicles employ suspension systems utilizing longitudinally extending trailing beams or rocker beams, also known as control arms. These beams are typically pivotally connected to the vehicle chassis or frame undercarriage at a first end, and attached to a transversely mounted axle at or near a second end. The first end may include a suspension bushing mounted within a suspension hanger depending from the vehicle frame.
For each axle, one beam is generally located near each of the left and right sides of the vehicle. Often, a suspension member, such as an air spring, leaf spring or coil spring, is positioned between the vehicle chassis and the axle mounting end of the suspension beam. In this configuration, when the vehicle axle encounters a rough surface and is displaced by movement of the tires attached thereto, the suspension member can manage the magnitude and speed of the displacement of the control arm while such beam pivots about the first end pivot connection.
A strong yet resilient first end pivot connection is critical to suspension performance because of loads imparted on the pivot end during suspension actuation and side or lateral loading which occurs as the vehicle turns. Current trends in heavy vehicle suspension designs include providing a generally annular resilient bushing mounted within an annular housing at the first end of the suspension beam. The bushing has a laterally positioned bore which, when the bushing is positioned within a suspension hanger, aligns with openings formed in both sides of the hanger. Generally, the bush is fastened within the hanger by passing a bolt through the hanger walls and the bushing bore. Some designs include an elongated bolt opening in each hanger wall to facilitate alignment of the suspension arm respective to the vehicle chassis.
The bush, often made from a hyperelastic material, is subject to periodic replacement due to wear and aging. Excessive wearing of the bush also occurs when the bolt securing it within the hanger has unwanted movement, often created by wear and tear or due to the bolt becoming loose during suspension movement. It is desirable to firmly secure the bush within the housing to limit wear and to eliminate unwanted movement of the bush within the suspension hanger which may affect suspension alignment. It is further desirable to mold the bush directly to the through bar, in this inventive device, a bar pin.
Another problem inherent in known suspension systems arises from the industry desire to decrease overall suspension weight and cost. Low weight and cost effective unitized suspension systems often include first pivot end bush housings without adjustments which makes bush replacement difficult, and often lead to premature replacement of the entire system when only bush replacement was necessary. Thus, it is desired to have a suspension system providing ease in bush replacement without necessitating the replacement of the whole system, and without requiring the use of specialized tools or equipment.
Hence, there is a need for an apparatus and and method for securing a bar pin end within a bush assembly and suspension hanger that overcomes one or more of the drawbacks identified above.